There were several incidents (ref. 1), but in particular Fukushima in 2011 changed a lot, as it was a modern type of power plant.

It reignited discussions regarding safety and (under the impression of 9/11) fears that nuclear power facilities could be targeted by terror attacks.

With current regulations new reactors can cost some 20 to 40 billion, making it one of the most expensive sources of electrical energy. Costs for decomissioning are significant as well. Both building and decomissioning costs are typically passed on to tax payers.

Also, permanent storage of used burning rods is hard, nobody wants nuclear waste buried in their neighborhood. Given its half life of ~240 000 years, it may also be difficult to communicate its dangers to future generations (ref. 2).

The currently most common sources of burning material (Uranium) stem from - large parts - politically controverse regions and may in sum last some estimated 80-100 years, quite short given some 10-20 years of construction time per plant.

This is not talking about thorium and salt reactors, but technical challenges and costs seem to be limiting for these technologies, in particular as long as the default infrastructure exists.

edit: the ‘new’ types are more complex and not suited for weapons in general.

1: https://en.wikipedia.org/wiki/List_of_civilian_nuclear_accidents?wprov=sfla1

2: https://www.youtube.com/watch?v=PUXwrWMS-x8

So I kind of want to split it halfway between you two: The reason all the regulation exists is because of how dangerous it is, the reason Nuclear is so expensive and time consuming is because of regulation. I reckon you could basically make a super dangerous Nuclear plant for not much more than a coal plant and in the same time frame. So, you could say it like “nuclear is too time consuming and expensive to be relevant”, or “nuclear is too dangerous to be relevant” and they’re both basically saying the same thing.

Would be a shame if someone were to be ripping out regulations left and right 🥲